uk.ac.starlink.ttools.filter

Class TableStats

java.lang.Object

uk.ac.starlink.ttools.filter.TableStats

public class TableStats
extends Object

Aggregates column statistics for a table. Factory methods are provided to accumulate statistics from table data.

Since:

3 Dec 2020

Author:

Mark Taylor

Field Summary

Fields

Modifier and Type	Field and Description
static double	MAD_SCALE Value by which Median Absolute Deviation is scaled to estimate SD.

Constructor Summary

Constructors

Constructor and Description
TableStats(UnivariateStats[] colStats) Constructor.

Method Summary

Modifier and Type	Method and Description
static double[]	calculateMads(StarTable table, RowRunner runner, java.util.function.Supplier<Quantiler> qSupplier, double[] medians) Calculates Median Absolute Deviations for each table column.
static TableStats	calculateStats(StarTable table, RowRunner runner, java.util.function.Supplier<Quantiler> qSupplier, boolean doCard) Calculates statistics from a given table.
UnivariateStats[]	getColumnStats() Returns the array of per-column statistics accumulators.
long	getRowCount() Returns the number of rows for which statistics have been accumulated.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MAD_SCALE

public static final double MAD_SCALE

Value by which Median Absolute Deviation is scaled to estimate SD.

See Also:

Constant Field Values

Constructor Detail

TableStats

public TableStats(UnivariateStats[] colStats)

Constructor.

Parameters:

colStats - array of per-column statistics accumulators

Method Detail

getColumnStats

public UnivariateStats[] getColumnStats()

Returns the array of per-column statistics accumulators.

Returns:

column stats

getRowCount

public long getRowCount()

Returns the number of rows for which statistics have been accumulated.

Returns:

row count

calculateStats

public static TableStats calculateStats(StarTable table,
                                        RowRunner runner,
                                        java.util.function.Supplier<Quantiler> qSupplier,
                                        boolean doCard)
                                 throws IOException

Calculates statistics from a given table.

Parameters:

table - table supplying data

runner - controls sequential/parallel processing

qSupplier - supplies quantile accumulators if quantiles are required, otherwise null

doCard - whether to count distinct values

Throws:

IOException

calculateMads

public static double[] calculateMads(StarTable table,
                                     RowRunner runner,
                                     java.util.function.Supplier<Quantiler> qSupplier,
                                     double[] medians)
                              throws IOException

Calculates Median Absolute Deviations for each table column.

Parameters:

table - input table

runner - controls sequential/parallel processing

qSupplier - supplies quantile accumulators

medians - per-column array of median values; MADs will be calculated only for elements with non-null values

Returns:

per-column array of MADs

Throws:

IOException